1. Field of the Invention
The present invention relates to a power feed socket that is installed, for example, in a vehicle and in which a cigarette lighter or a plug of the other electrical product is inserted to supply power thereto, and a contact point unit used in the power feed socket.
2. Description of the Related Art
For example, Japanese Utility Model Examined Publication No. 2-27337 discloses this kind of power feed socket for cigarette lighter, for example.
A case (lighter body) as insert destination of a lighter plug made of metal is molded by deep drawing work to have a bottomed cylindrical shape, and has a through hole in the bottom wall. An insulator is disposed in the case to have the bottom wall therebetween, and an insulator platform, a first terminal, an insulating washer, and a second terminal are disposed in that order outside of the case. A bolt-shaped power feed terminal that is inserted through a hole formed in each member from an inside of the case is tightened from an outside of the case by a nut, thereby assembling the power feed terminal to the case in an insulating state. The first terminal is in an insulating state to the power feed terminal, the second terminal is connected to the power feed terminal, and a fuse is disposed between the second terminal and the first terminal.
A bimetal holding a heater case as an electrode of a lighter plug tip pushed into the case is attached in a head of the power feed terminal, and an electrode of a plug side surface is provided to be in contact with the case. That is, the bimetal is configured as a first contact point to the lighter plug and the case is configured as a second contact point for power feeding. When the heater generates heat to reach a predetermined temperature, the bimetal is deformed to release the lighter plug from a pushing-in position to end the power feeding.
On the other hand, when an abnormal temperature rise occurs due to a failure, the fuse is melted down to break off an electrical connection between the first terminal and the second terminal and stop the power feeding.
It should be noted that in the above structure, when the head of the power feed terminal is configured as the first contact point in a state where the bimetal is removed or the bimetal is attached, the power feeding to the other electrical product is possible.
In the above cigarette lighter, however, for insulating the power feed terminal from the case as the second contact point in the first contact point side of the fuse assembly, components such as the insulator or insulating platform leading to cost increase are required. In addition, the power feed terminal itself has a screw portion formed in a bolt shape, therefore leading to a high increase in cost.
In addition, even except for the bimetal, an elaborate assembly process that the power feed terminal is inserted in a great number of components such as the insulator, the case bottom wall, the insulator platform, the first terminal, the insulating washer and the second terminal, which is then tightened by the nut, is forced to be executed. At this time, for disposing the insulating washer between the first terminal and the second terminal that are jointed by the fuse and therefore have a low degree of freedom in dealing, the power feed terminal is forced to be put through the first terminal and the second terminal individually, particularly causing difficulty with the working process.
That is, the conventional structure has a problem that a high increase in cost occurs both in terms of the components and the assembly process.